1. Technical Field
The present invention relates to a superabsorbent polymer having improved anti-caking properties and a method of preparing the same and, more particularly, to a superabsorbent polymer having improved anti-caking properties, which includes a superabsorbent polymer, microparticles, and water, and wherein to improve anti-caking properties of the superabsorbent polymer, the temperature of the superabsorbent polymer or water upon addition of water or the aging time upon stirring is adjusted, thereby preventing caking of the particles.
2. Description of the Related Art
Superabsorbent polymers (SAPs) are synthetic polymers able to absorb water about 500˜1000 times their own weight. Such superabsorbent polymers have actually begun to be used for sanitary items, and are being currently widely utilized in not only hygiene products such as baby disposable diapers and menstrual sanitary pads, but also in gardening soil repair agents, water stop agents for civil construction, seeding sheets, freshness retaining agents in food distribution sectors, and fomentation materials. Compared to conventional absorbent materials, superabsorbent polymers have an outstanding absorption capacity and thus the market value thereof is increasing with the wider range of applications thereof. In particular, superabsorbent polymers having excellent water absorbability are mainly employed in hygiene products such as baby diapers and adult diapers. Furthermore, upon application to hygiene products, superabsorbent polymers present in the diapers play a role in absorbing and retaining urine. Meanwhile, in the course of producing diapers, superabsorbent polymers may undergo high pressure and physical impact, and thus the properties thereof may be remarkably deteriorated, resulting in poor diaper performance.
In this regard, Korean Patent Application Publication No. 2012-0081113 discloses a method of preparing an absorbent polymer including water-insoluble inorganic particles. However, such a conventional technique is problematic because surface stickiness of the superabsorbent polymer becomes high with an increase in moisture content on the surface thereof, undesirably incurring agglomeration, poor processability, and low productivity as mentioned above, thus making it difficult to satisfy both high moisture content and high processability.
Meanwhile, when water is added to the superabsorbent polymer at room temperature or at relatively low temperature, temporal limitations of water diffusion are imposed on the surface of the superabsorbent polymer. Thus, in order to reduce a caking phenomenon, the aging time of the unstable superabsorbent polymer containing water has to be increased, undesirably lowering productivity. Hence, there are required methods of uniformly adding water to the superabsorbent polymer without caking. Even when no caking occurs upon addition of water, caking has to be prevented under long-term loads. To this end, when water is introduced into the superabsorbent polymer, efficient techniques for preventing caking of the superabsorbent polymer while improving properties and imparting novel functionalities are needed.